It's essential to clarify some terms here to avoid confusion. The phrase "multiple personalities" is outdated and doesn't accurately describe the concept it refers to. The correct term is "Dissociative Identity Disorder" (DID), which was previously known as multiple personality disorder.
DID is a rare and severe mental disorder characterized by the presence of two or more distinct identity states, often referred to as "alters" or "personalities." These identities may have different names, characteristics, memories, and ways of interacting with the world. It is crucial to note that DID is a complex and serious psychological condition, and it should not be confused with the personality traits associated with various personality types like INFJ or ESTP.
Personality types, such as those described in the Myers-Briggs Type Indicator (MBTI) system like INFJ or ESTP, refer to the individual's cognitive preferences, decision-making styles, and patterns of behavior. These preferences are thought to be relatively stable over time and do not imply the presence of multiple identities or dissociation.
In short, having a strong sense of self, as described in personality typing systems like MBTI, does not mean a person has multiple personalities (DID). They are entirely different concepts related to different aspects of a person's psychological makeup. Additionally, it's important to remember that personality typing systems like MBTI are not scientifically validated personality assessments and should be taken with a grain of salt. They can be fun and insightful but should not be used to diagnose or define mental health conditions.